- recording or playback of information by relative movement between a record track and a transducer, the transducer directly producing, or being directly actuated by, modulation in the track being recorded or played-back, and the extent of modulation corresponding to the signal being recorded or played-back;

- apparatus and machines for recording or playback, and parts thereof such as heads;

- record carriers for use with such apparatus and machines;

- associated working of other apparatus with such apparatus and machines;

- [N: relative positioning or movement of transducers and record carriers before, during or after transducing operation, e.g. for accessing record carriers or parts thereof, or for track change, selection or acquisition or for track following or for accessing parts of tracks;]

- [N: driving or moving of heads or record carriers or both heads and record carriers for increasing, maintaining or decreasing the relative speed before, during or after transducing operation]

In this subclass, the following terms or expressions are used with the meanings indicated :

- "head" includes any means for converting sinusoidal or non-sinusoidal electric wave-forms into variations of the physical condition of at least the adjacent surface of the record carrier, or vice versa;

- "record carrier" means a body, such as a cylinder, disc, card, tape, or wire, capable of permanently holding information, which can be read-off by a sensing element movable relatively to the record carrier.

[N: Notes

Documents concerning relative positioning or movement of transducers and record carriers are classified in groups G9B/3 to G9B/7 and G9B/21when only the transducer is controlled and in groups G9B/15, G9B/17 and G9B/19when only the record carrier is controlled.When both record carrier and head are controlled, the documents are classified in G9B/15.022, G9B/15.023, G9B/19 andG9B/27.001. When a plurality of record carriers are controlled, the documents are classified in G9B/15.135, G9B/17.041, G9B/17.051 andG9B/27.001. By "access" is meant an operation including a relative movement for positioning between record carrier and head before, during or after transducing; this operation including "seek", "select", "change", "acquire" and "follow" functions for at least a part of a track on at least one record carrier. By "programmed access" is meant a sequence of access operations the result of the sequence being to acquire a want ed sequence of parts of tracks or a wanted sequence of tracks. Relative movement between head and record carrier also covers the movement of a coupling beam such as a light beam between the head and a stationary record carrier. "Movement of the head" also covers any virtual movement or any physical movement such as obtained by switching between successive transducing parts of the head or by moving the transducing zone of the head, i.e. by "scanning". If different transducing parts of the head are switchable, the number of transducing parts should be much smaller than the number of individual storage areas of the record carrier. Attention is drawn to the notes of subclass G11C.]

In group G9B/7.171, multi-aspect classification is applied, so that if subject matter is characterised by aspects covered by more than one of its subgroups, the subject matter should be classified in each of those subgroups.]

Classification in these groups is done according to the means required for the conditioning, disposition, mounting and positioning of the heads and record carriers, with regard to the microscopic size of the transducing zones]

Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G9B/3 to G9B/7 or by different subgroups of group G9B/9; Record carriers therefor [N: driving or moving of heads G9B/3.008, G9B/5.147, G9B/7.041, G9B/21.003]{G11B 11/00}

[N: Notes

[C0201]

In this group, the expression "+IDT" is used to indicate:

- that the documents classified here were classified in IDT-groups concerning:

"Methods or devices wherein the recording and the reproducing operations are carried out according to different methods"

- that they were reclassified administratively from said IDT-groups to this group

Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function (driving or guiding heads G9B/3 to G9B/7, G9B/21){G11B 15/00}